Wiper blade

ABSTRACT

The invention starts from a wiper blade ( 20 ) of a windshield wiper with a wiper strip support ( 22 ) and wiper strip ( 24 ), which feature end caps ( 28 ) on their ends, whose inner cross-sectional profile is adapted to the cross-sectional profile of the wiper strip support ( 22 ). It is proposed that a guide rib ( 42, 48, 50 ) running transverse to the longitudinal direction ( 58 ) of the wiper blade ( 20 ) and having a guide surface ( 44, 54 ) be formed laterally on at least one of the end caps ( 28 ).

STATE OF THE ART

The invention starts from a wiper blade in accordance with thepre-characterizing clause of claim 1.

Known windshield wipers have a wiper arm constructed of a fastening partand an articulated part, which is connected to the fastening part in anarticulated manner and has a wiper rod. Connected to the free end of thewiper rod in an articulated manner is a wiper blade constructed of awiper strip and a wiper strip support, as a rule a supporting bracketsystem with a center bracket and, if necessary, subordinate brackets,e.g., an intermediate bracket and/or claw brackets, which hold the wiperstrip. The brackets are also connected to the subordinate brackets in anarticulated manner so that the wiper strip can adapt to the curvature ofthe vehicle window during the rotating movement. These types ofwindshield wipers are known from DE 37 44 237 A1, for example. Thejoints between the brackets are formed as a rule by plastic parts, whichsimultaneously cover the front side of the profile of the higher-orderbracket.

In addition, a wiper strip support in the form of a supporting elementmade of an elastic high-strength plastic for a wiper strip is known fromDE 197 38 232 A1, which has a curvature in an unloaded state that isdesigned so that uniform application force is produced when the wiperstrip is applied completely to the vehicle window during operation ofthe wiper blade. In addition, similar wiper blades with a supportingelement are known in which pre-bent spring rails are laterally insertedinto a plastic profile. Caps made of plastic are mounted on the frontsides as a conclusion of the profile. Both a supporting bracket systemas well as a supporting element in the sense described above shall beunderstood in the following as a wiper strip support.

Wiper blades frequently tend to vibrate during the wiping process.During the rotating movement, the speed with which the wiper bladeglides over the windshield continuously increases from the inner radiustowards the outer radius. The frictional forces acting transverse to thelongitudinal direction of the wiper blade, which are a function of thegliding speed, decrease with increasing glide speed so that a torque isproduced around the vertical axis of the wiper blade, which changes itsdirection in the reverse positions. This changing torque stresses thebearing position between the wiper arm and the wiper blade. Above allwith relatively long wiper blades, the guidance on the joint between thewiper blade and the wiper arm is not sufficiently stable to inhibitvibrations. The wiper blade is incited to vibrate since a wiper blade isa slim, elastic component and because of great speed differences in thefrictional conditions between the drive-side inner area and the outerarea of the wiper blade as well as due to the stick-slip effects. Thisleads, particularly on the inner circle of the wiper blade whereespecially low friction speeds are predominant, to undesired lateralmovements, which starting at a certain size can lead to the wiper bladeimpacting the wiper arm and causing clattering noises. This isparticularly critical if the vehicle windows are dry, dirty, icy, or notmoist enough or there is snow on the vehicle window. Because the wiperblade can briefly lose contact with the vehicle window in this case, thewiped image is also unsatisfactory. The more bracket parts the wiperblade has, the sooner it tends to rattle. In addition, light wiperblades with low spring rigidity are less favorable than others.

In addition, a device to guide the wiper blade, which has a first and asecond part, is known from DE 197 31 683 A1. It is arranged in the areaof the coupling location of the claw bracket and permanently connectedto the articulated part of the wiper arm, e.g., via adhesion, welding,soldering, clipping, clamping, etc. The first part of the device hasguide cheeks, which grip around the articulated location of the clawbracket and guide laterally with respect to the wiper arm. The secondpart also has guide cheeks, between which the first part is guided in atelescoping manner so that its guide cheeks can be held briefly and acollision with the vehicle window need not be feared even when thevehicle window has strong curvatures. The first part is appropriatelyconnected with the device so that it is secure from loss, for example,via a flexible element.

The device can be manufactured and composed of individual sheet metalparts, but it is preferably a plastic injection molded part made of asuitable plastic. In any case, additional components are required toguide the wiper blade, whereby increased expenditures for fabricationand assembly, and additional material costs are incurred. Air gaps areprovided as a rule between the guide surfaces of the device in order toprevent the joint between the wiper blade and the wiper arm from jammingdue to wiper-arm geometry that is influenced by tolerances such as rightangles on the wiper rod. Clattering noise can also occur in this case,because, though the lateral vibrations are highly diminished, they arenot avoided completely.

ADVANTAGES OF THE INVENTION

According to the invention, a guide rib running transverse to thelongitudinal direction of the wiper blade and having a guide surface isformed laterally on at least one of the end caps. An additionalcomponent is not required to guide the wiper blade since the guide rib,which represents a part of a device to guide the wiper blade, forms onecomponent with the end cap. The manufacturing expense and assemblyexpense are advantageously reduced as a result. The end cap can beguided with the guide rib directly or with the use of a guide bracket inthe profile of the wiper arm, into which the end of the wiper bladepointing to the windshield wiper drive dips. As a rule, it is onlynecessary for one of the two end caps of the wiper blade to feature aguide rib. However, in order to avoid assembly errors, it is expedientto place the same end cap with a guide rib on both ends.

The guide bracket is preferably a plastic part and is inserted into thearticulated part, for example, clipped in. As a result, it can also bemounted simply and with low expense. In addition, it can also improvethe gliding properties between the end cap and the wiper arm and make amore favorable guidance profile possible than the inner profile of thewiper arm. Another advantage of the wiper blade guidance is that it iscovered by the wiper arm to a large extent, does not require anyadditional installation space, and also makes a compact design of thewindshield wiper possible in the wiper arm and wiper blade area. Acompact windshield wiper produces less wind noise and possesses a betterdesign.

The guide bracket features an outer profile adapted to the innerdimensions of the articulated part. It is supported on the inner contourof the articulated part. In order to lengthen the guide surfaces, aportion of the guide bracket can project beyond a side wall, which, inthe area of the dipping end cap, serves as a bearing surface for theguide surface of the guide rib. Because of the inserted guide bracket,the articulated part is only lengthened in one area required for wiperblade guidance and otherwise remains unchanged. Analogous to the guidebracket, the shape of the guide rib is also adapted to the profile ofthe articulated part. If the articulated part has a U-shapedcross-sectional profile, for example, the allocated end cap can haveformed-on guide ribs on both sides, whose guide surfaces runapproximately rectangular to the base surface of the end caps and areguided onto the side walls of the U-profile with a slight amount ofplay. Because of the two-sided arrangement, the wiper blade can beguided in both wiping directions.

In one embodiment of the invention, the end cap features a guide ribformed on one side with angle of inclination to the base surface of theend cap, which is slightly less than 90°. This end cap shall be assignedto a wiper arm with a roof-like cross-sectional profile, whereby theguide rib is guided onto a side wall whose inclination is adapted to theshape of the guide rib. If the end cap dips into the wiper arm, theguide rib is positioned on the side wall of the wiper arm or the guidebracket, whereby the wiper blade is slightly pre-stressed transverse toits longitudinal direction. Because of the pre-stress there isadvantageous contact between the guide rib and the guide bracket inevery case since manufacturing tolerances and wear of the individualcomponents are balanced out. In addition, the end cap also does not losecontact with the wiper arm because of the pre-stress even if the guiderib lies in the wiping direction in front of the wiper blade during awiping movement. However, the guide rib is expediently arranged in sucha way that, in the wiping direction that requires the greatestpropelling force, it lies in the wiping direction behind the wiperblade.

The wiper blade is guided on the critical inner circle of the wiperfield so that vibrations are avoided and the profile of the articulatedpart of the wiper arm can be used as a bearing surface. In addition, thejoint between the wiper arm and wiper blade is relieved since the torquearound the vertical axis of the wiper blade is supported on a wide basisbecause of the lateral guidance on the inner circle.

DRAWINGS

Additional advantages are yielded from the following description of thedrawings. Exemplary embodiments of the invention are depicted in thedrawings. The drawings, the description, and the claims contain numerousfeatures in combination. The expert will also observe individualfeatures expediently and combine them into additional, meaningfulcombinations.

The drawings show:

FIG. 1A schematic side view of a wiper arm with a wiper blade that isconnected in an articulated manner.

FIG. 2A section corresponding to Line II-II in FIG. 1.

FIG. 3A variation of FIG. 2.

FIG. 4A perspective partial view of FIG. 3 in a modified relativeposition between an articulated part and a wiper blade.

FIG. 5 An enlarged perspective depiction of an end cap in accordancewith FIG. 4.

FIG. 6 Another variation in accordance with FIG. 2.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

A wiper arm 10 constructed of an articulated part 12 and a wiper rod 14is connected to a wiper blade 20 via a joint 18 and a connecting piece16 (FIG. 1). The wiper blade 20 has an elastic, non-articulated wiperstrip support 22, which is embodied as a spoiler and bears a wiper strip24. The joint 18 between the wiper rod 14 and the wiper blade 20, andthe elasticity of the wiper strip support 22 make it possible for thewiper strip 24 to be able to adapt to the curvature of a windshield 26during the wiping movement. In doing so, the wiper blade 20 moves in aplane vertical to the windshield 26 relative to the wiper arm 10,whereby the relative stroke movement on the end of the wiper blade 20 isespecially great.

A wiper blade guide is provided for lateral guidance of the wiper blade20 on the end facing the wiper arm 10. It is composed of an end cap 28with laterally formed-on guide ribs 48, which run transverse to thelongitudinal direction 58 of the wiper blade 20, and of the articulatedpart 12 with an inserted guide bracket 36, which serves as a bearingsurface for the guide ribs 48. The end cap 28 made of plastic encirclesthe wiper strip support 22 and a portion of the wiper strip 24 togetherwith two spring rails 40 made of spring steel, which are inserted intolateral longitudinal grooves of the profile (FIG. 2). It forms acovering for the wiper blade 20 in the end area and simultaneouslyfastens the spring rails 40 axially and together with the connectingpiece 16. The guide ribs 48 are formed onto the end cap duringmanufacturing. They have lateral guide surfaces 44, which run verticalto a base surface 56 of the end cap 28 and in an assembled state in theprofile of the wiper arm 10, e.g., when using a guide bracket 36, areguided on the two side walls 34 of the articulated part 12. In theembodiment according to FIG. 2, the articulated part 12 has a U-shapedcross-sectional profile. The guide bracket 36 is also a plastic part. Itlines the inner contour of the articulated part 12 in the area of theend cap 28 and is supported on the side walls 34 and on the coveringwall 30.

In one embodiment of the invention, guide ribs 42 or 50 with guidesurfaces 44 or 54 are formed on only one side part 32 of the end cap 28(FIG. 3 through FIG. 6). In addition, the guide surfaces 44 feature anangle of inclination a to the base surface 56, which is slightly lessthan 90° and is adapted to the inclination of the side wall 34 of thearticulated part 12. This end cap 28 shall be assigned to a wiper arm 10whose articulated part 12 features a roof-like cross-sectional profilehaving side walls 34 of different inclinations. The inclination of theguide surfaces 44 is adapted to the steeper side wall 34 and the guideribs 42 are adjacent to this side wall 34 in an assembled position. Inthe wiper arm's 10 parking position, the flatter side wall 34 pointsdownward and acts as a spoiler during the wiping operation.

So that the guide surfaces 44 are long enough to also have constantcontact with the bearing surface on the side wall 34 of the articulatedpart 12 even in the case of greater stroke movements, in the embodimentin accordance with FIG. 3 through FIG. 5, the guide ribs 42 projectbeyond the outer profile of the end cap 28 on one of the sides facingaway from the base surface 56 by an area 46. Moreover, the bearingsurface on the articulated part 12 is lengthened by the guide bracket36, which projects beyond the side wall 34 by a part 38. A possibleextreme position between the articulated part 12 and the wiper blade 20is depicted in FIG. 4.

According to the invention, the guide bracket 36 is inserted into thearticulated part 12, for example, clipped in, clamped or glued. As aresult, the articulated part 12 is changed in a simple manner and onlyin the area of the dipping end cap 28, and otherwise corresponds to thestandard design. As a result, a wiper arm 10 can also be subsequentlyequipped with this type of wiper blade guidance.

According to another embodiment (FIG. 6), the guide bracket 36 iscomposed of a metallic material and the guide ribs 50 are shortened ascompared with the height of the end cap 28. This end cap 28 is adjacentwith the guide surfaces 54 in one area and its upper part is adjacentwith the guide bracket 36 in another area. A flute 52 forms thetransition between the areas.

1. Wiper blade (20) of a windshield wiper with a wiper strip support(22) and wiper strip (24), which feature end caps (28) on their ends,whose inner cross-sectional profile is adapted to the cross-sectionalprofile of the wiper strip support (22), characterized in that a guiderib (42, 48, 50) running transverse to the longitudinal direction (58)of the wiper blade (20) and having a guide surface (44, 54) is formedlaterally on at least one of the end caps (28).
 2. Wiper blade (20)according to claim 1, characterized in that it shall be assigned to awiper arm (10), which has a U-shaped cross-sectional profile into whichthe end cap (28) is guided in an assembled position by guide ribs (48)on both sides on the side walls (34).
 3. Wiper blade (20) according toclaim 1, characterized in that it shall be assigned to a wiper arm (10),which has a roof-like cross-sectional profile with a steeper side wall(34), whereby the guide surface (44, 54) on the guide rib (42, 50)formed on one side is guided only on the steeper side wall (34) in anassembled position and the inclination of the guide surface (44, 54) isadapted to the inclination of the side wall (34).
 4. Wiper blade (20)according to claim 3, characterized in that the guide surface (44, 54)has an angle of inclination to a base surface (56), which is slightlyless than 90°.
 5. Wiper blade (20) according to claim 1, characterizedin that on the side that faces away from the base surface (56), theguide rib (42, 48) projects beyond the outer profile of the end cap (28)by an area (46).
 6. Wiper blade (20) according to claim 3, characterizedin that the guide rib (50) is so shortened as compared with the heightof the end cap (28) that the end cap (28) touches the inner contour ofthe wiper arm (10) with its upper part.
 7. Wiper blade (20) according toclaim 1, characterized in that a guide bracket (36) made of plastic,which serves as a bearing surface for the guide surface (44, 54), isinserted into the wiper arm (10).
 8. Wiper blade (20) according to claim1, characterized in that the guide bracket (36) made of plasticlengthens, in cross-section, the side wall (34) of the wiper arm (10)facing the guide surface (44, 54).
 9. Wiper blade (20) according toclaim 2, characterized in that on the side that faces away from the basesurface (56), the guide rib (42, 48) projects beyond the outer profileof the end cap (28) by an area (46).
 10. Wiper blade (20) according toclaim 3, characterized in that on the side that faces away from the basesurface (56), the guide rib (42, 48) projects beyond the outer profileof the end cap (28) by an area (46).
 11. Wiper blade (20) according toclaim 4, characterized in that on the side that faces away from the basesurface (56), the guide rib (42, 48) projects beyond the outer profileof the end cap (28) by an area (46).
 12. Wiper blade (20) according toclaim 4, characterized in that the guide rib (50) is so shortened ascompared with the height of the end cap (28) that the end cap (28)touches the inner contour of the wiper arm (10) with its upper part. 13.Wiper blade (20) according to claim 2, characterized in that a guidebracket (36) made of plastic, which serves as a bearing surface for theguide surface (44, 54), is inserted into the wiper arm (10).
 14. Wiperblade (20) according to claim 3, characterized in that a guide bracket(36) made of plastic, which serves as a bearing surface for the guidesurface (44, 54), is inserted into the wiper arm (10).
 15. Wiper blade(20) according to claim 4, characterized in that a guide bracket (36)made of plastic, which serves as a bearing surface for the guide surface(44, 54), is inserted into the wiper arm (10).
 16. Wiper blade (20)according to claim 5, characterized in that a guide bracket (36) made ofplastic, which serves as a bearing surface for the guide surface (44,54), is inserted into the wiper arm (10).
 17. Wiper blade (20) accordingto claim 6, characterized in that a guide bracket (36) made of plastic,which serves as a bearing surface for the guide surface (44, 54), isinserted into the wiper arm (10).